Rock group Bon Jovi is offering fans an incentive to buy its latest CD rather than obtain a pirated copy from the internet.

Users buying a legitimate copy of Bounce will find a 13-digit number inside the packaging.

This serial number can be used on the group's website to entitle the user to special privileges, including tickets for concerts before they go on general release, unseen footage of the band and downloads of live versions of songs.

It is the latest in a long line of attempts by the music industry to crack down on pirated CDs and the practice of downloading free music from the internet.

Value-added

According to Larry Mattera, head of new media at Bon Jovi's record label Island Def Jam, the band wanted to find imaginative ways of persuading fans to buy legitimate copies of their new album.

CD sales have slumped

"We need to ensure there is enough value in the CD itself to drive purchases," he told the BBC's Go Digital programme.

"There is value in music but that has got lost in the last few years with the advent of the internet and the ability to file-share."

But this may not be enough to stop music pirates. Copies of Bounce are already available online, with thousands of people downloading it.

The album is topping the download charts on one site which offers a guide to pirated music.

Fighting pirates

The music industry has come down hard on file-sharing sites such as Napster that allow users to swap music over the internet.

It has proved a game of cat-and-mouse however as every time one is closed down, another opens.

The music industry blames a fall in the sales of CDs on the advent of pirated music although a survey by US-based analysts Forrester found no evidence that consumers of digital music bought less CDs.

Professional pirates manufacture large numbers of CDs in pressing plants based in South East Asia, Eastern Europe and Latin America.

CD burning among amateur music fans is rife particularly in Germany.

Music labels are experimenting with copy protection software to defy the pirates.

A previous attempt by Bon Jovi's label to embed extra features into legitimate CDs was a failure because the information was contained in the disc itself meaning it showed up on pirated copies as well.